Levocetirizine is an antihistamine medication that comes as a breakable tablet and an oral solution. It is available both over-the-counter and as a prescription.
Levocetirizine relieves the annoying symptoms of seasonal and year-round allergies, such as a runny nose, sneezing, and itchy or watery eyes. It can also treat chronic hives, which are itchy red bumps or rashes on the skin.
Levocetirizine is suitable for people ages 6 months and older, but dosages and side effects may vary.
This article describes the possible side effects of levocetirizine and how to manage them.
Levocetirizine can cause side effects that vary depending on age group. The table below shows the most common side effects across age groups.
| Age group | Common side effects |
|---|---|
| Adults and adolescents (12 years and older) | • sleepiness • nose and throat irritation (nasopharyngitis) • fatigue • dry mouth • sore throat (people in this group also experienced fainting and weight gain, but these were much less common) |
| Children 6 to 12 years | • fever • cough • sleepiness • nosebleeds |
| Children 1 to 5 years | • fever • diarrhea • vomiting • ear infection |
| Infants 6 to 11 months | • diarrhea • constipation |
These side effects are typically temporary, lasting a few days to a few weeks. Talk with your doctor if side effects do not go away, get worse, or become too difficult to tolerate.
FDA warning of severe itching
In May 2025, the
This typically happens to people who’ve been taking levocetirizine or cetirizine daily for a long time—usually for a few months or more.
The itching usually starts within 1 to 5 days of stopping the drug. In some cases, the itch was so intense and widespread that it significantly impacted the person’s quality of life.
If you wish to stop taking levocetirizine or cetirizine, your doctor may recommend tapering off it slowly.
While rare, some side effects are serious and require immediate attention. They include:
- heart palpitations
- increased heart rate (tachycardia)
- nervous system issues, such as:
- seizures
- tremors
- dizziness
- mental health changes, such as:
- aggression
- agitation
- hallucinations
- depression
- suicidal thoughts
- difficulty urinating (urinary retention)
- liver problems (hepatitis)
If you develop serious side effects while taking levocetirizine, call your doctor right away. If you think you’re having a medical emergency, immediately call 911 or your local emergency number.
Allergic reaction
For some people, levocetirizine can cause an allergic reaction. However, this side effect wasn’t reported in the drug’s studies.
If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest an alternative treatment.
If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.
Yes, the amount of levocetirizine you take matters. Clinical trials showed that the more you take, the more likely you are to feel drowsy. For example, people taking a 10 milligram (mg) dose felt more drowsy than those taking the standard 5 mg dose.
Taking more than the recommended daily amount increases your risk of side effects without necessarily providing better symptom relief.
Reporting side effects
After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medication safer for everyone by giving doctors and researchers more information about how the drug works in real life.
If you develop a side effect while taking levocetirizine and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.
Antihistamines like levocetirizine are well known for causing drowsiness. For this reason, avoid driving a car or operating heavy machinery until you’re sure how the medication affects you. Drinking alcohol or taking other drugs, such as opioids, benzodiazepines, and sleep medications, can worsen the sedative effects.
Other tips for minimizing side effects include:
- Take it in the evening: Since sleepiness is a common side effect, taking your dose at night can help you avoid being tired during the day.
- Follow the dose: Never take more than your doctor prescribes or the package recommends.
- Avoid Alcohol: Alcohol can make the “brain fog” and sleepiness much worse.
- Stay Hydrated: This may help with the dry mouth side effect.
- Check your other medications: Always tell your doctor about other vitamins or supplements you take to avoid negative interactions.
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Levocetirizine effectively treats allergies and hives, but it often causes sleepiness and fatigue, especially at higher doses.
It’s very important to follow your doctor’s dosing advice to avoid serious complications.
Because of levocetirizine’s sedative effects, it’s a good idea to avoid driving, operating heavy machinery, drinking alcohol, and taking other medications that can cause drowsiness.
If you develop any side effects that bother you, talk with your doctor for advice.
Disclaimer
Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication.
The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.